The bonds are secured by BART's sales tax revenue, consisting of 75% of revenue from a 0.5-cent sales tax collected in the three-county service area, with the remaining 25% distributed to the Metropolitan Transportation Commission (MTC). The California Department of Tax and Fee Administration collects the district's sales tax along with the state and other local sales taxes, and distributes the sales tax to the bond trustee prior to releasing it for BART's operating and capital funds. Additionally, we understand that BART has obtained third-party green bond verification that the bonds comply with the Climate Bond Standards Board's Low Carbon Land Transport Standard. The 2017 refunding series A and 2017 refunding series B bonds will not have a debt service reserve fund. Proceeds will be used to advance refund all or a portion of BART's series 2010, series 2012A, and series 2012B sales tax revenue bonds for debt service savings.

The rating reflects our view of BART's:

Exceptionally deep and diverse three-county service area that is home to 3.6 million residents, or nearly half of the San Francisco Bay Area population;

Leading regional economy in terms of industrial diversity, job growth, and affluence; and

Very strong maximum annual debt service (MADS) coverage of about 4.78x based on 2017actual revenues and the refunding debt service schedule.

Certain terms used in this report, particularly certain adjectives used to express our view on rating relevant factors, have specific meanings ascribed to them in our criteria, and should therefore be read in conjunction with such criteria. Please see Ratings Criteria at www.standardandpoors.com for further information. Complete ratings information is available to subscribers of RatingsDirect at www.capitaliq.com. All ratings affected by this rating action can be found on the S&P Global Ratings' public website at www.standardandpoors.com. Use the Ratings search box located in the left column.